Outcomes of Initial Observation Versus Upfront Microsurgical Resection for Small to Medium-sized Vestibular Schwannomas.

[OBJECTIVE] To assess postoperative outcomes and predictive factors of patients observed prior to microsurgery and those undergoing upfront resection for small and medium-sized VS.

[STUDY DESIGN] Retrospective cohort.

[SETTING] Tertiary referral center.

[PATIENTS] VS patients who had microsurgery from 2003 to 2018 for tumors up to 2.5 cm.

[MAIN OUTCOME MEASURES] Postoperative outcomes including facial nerve function and interventions, complications, extent of resection, and salvage therapy.

[RESULTS] Of 220 patients, 120 were initially observed, and 100 pursued upfront microsurgery. There was no significant association between initial observation and upfront microsurgery for postoperative facial nerve function at 2 to 3 weeks (p = 0.18) or 12 months (p = 0.5), facial nerve intervention (p = 0.5), major/minor complications (p = 0.48/0.63), recurrence (p = 0.8), subtotal resection (p = 0.6), or salvage therapy (p = 0.9). Time from initial consultation to surgery did not significantly impact outcomes. Intrameatal tumors were more likely to be observed (odds ratios [OR] 2.93; 95% CI 1.53-5.63; p = 0.001). Patients with larger tumor volume (OR 0.52; 95% CI 0.37-0.72; p < 0.0001), brainstem compression (OR 0.28; 95% CI 0.09-0.91; p = 0.03), or higher PTA were less likely to undergo observation (OR 0.99; 95% CI 0.97-0.997; p = 0.02). On multivariable analysis, predictive factors for observation were smaller tumor volume (OR 0.53; 95% CI 0.38-0.75; p < 0.001), lower PTA (OR 0.99; 95% CI 0.98-0.999; p = 0.04), and diabetes (OR 2.54; 95% CI 0.95-6.83; p = 0.06).

[CONCLUSIONS] Patients with worse hearing, larger tumor volume, and brainstem compression were more likely to pursue upfront microsurgery. A watchful waiting period does not appear to worsen outcomes and can be considered for patients with better hearing and smaller tumors without brainstem compression.